Showing papers by "Oluwole Daniel Makinde published in 2022"

Analysis of Joule heating and chemical reaction effects in electroosmosis peristaltic transport of couple‐stress and micropolar fluids

Abstract: This article features the reaction of electroosmosis peristaltic transport of combined couple‐stress and micropolar fluid in an inclined asymmetric channel through a porous medium. Mathematical modeling is given in the presence of Joule heating, thermal radiation, and heat flux effects. The relevant equations are computed subject to long wavelength and small Reynolds number approximation. The coupled system resulting equations have been executed computationally to plot different effects graphically. A detailed analysis of the results is given through graphs. Graphs are plotted for velocity, temperature, concentration, and pumping characteristics. The impact of each significant parameter on flow, species, and thermal characteristics is enumerated in these studies. The influence of couple stress and electroosmosis parameters are also simulated. This problem is very significant to the discussion of chemical separation/fraternization procedures and bio‐microfluidics devices for the resolution of the diagnosis.

Rheological Modeling of Metallic Oxide Nanoparticles Containing Non-Newtonian Nanofluids and Potential Investigation of Heat and Mass Flow Characteristics

Abstract: Nanofluids have great potential due to their improved properties that make them useful for addressing various industrial and engineering problems. In order to use nanofluids on an industrial scale, it is first important to discuss their rheological behavior in relation to heat transfer aspects. In the current study, the flow characteristics of nanofluids are discussed using a mathematical model that is developed by fundamental laws and experimental data. The data are collected in the form of viscosity versus shear rate for different homogeneous ethylene glycol- (EG) based nanofluids, which are synthesized by dispersing 5–20% nanoparticle concentrations of SiO2, MgO, and TiO2 with diameters of (20–30 nm, 60–70 nm), (20 nm, 40 nm), and (30 nm, 50 nm), respectively. The data are fitted into a rheological power-law model and further used to govern equations of a physical problem. The problem is simplified into ordinary differential equations by using a boundary layer and similarity transformations and then solved through the numerical Runge–Kutta (RK) method. The obtained results in the form of velocity and temperature profiles at different nanoparticle concentrations and diameters are displayed graphically for discussion. Furthermore, displacement and momentum thicknesses are computed numerically to explain boundary-layer growth. The results show that the velocity profile is reduced and the temperature profile is raised by increasing the nanoparticle concentration. Conversely, the velocity profile is increased and the temperature profile is decreased by increasing the nanoparticle diameter. The results of the present investigation regarding heat and mass flow behavior will help engineers design equipment and improve the efficacy and economy of the overall process in the industry.

Entropy analysis for MHD blood flow of hybrid nanoparticles (Au–Al 2 O 3 /blood) of different shapes through an irregular stenosed permeable walled artery under periodic body acceleration: Hemodynamical applications

Abstract: The current study investigates the entropy generation for hybrid nanoparticles (Au–Al2O3/blood) through a vertical irregular stenosed artery in the presence of an external magnetic field, Joule heating, viscous dissipation, and heat source considering two-dimensional pulsatile blood flow and periodic body acceleration. The blood flow is assumed to be unsteady, laminar, viscous, and incompressible, and the artery walls are considered as permeable. The Reynolds temperature-dependent viscosity model is used to determine the variable viscosity effects. The governing momentum and energy equations are solved using Crank–Nicolson finite difference method by employing an appropriate coordinate transformation to build an accurate mesh using rectangular mesh units. Outcomes of the work are represented graphically for velocity, wall shear stress (WSS), volumetric flow rate, resistance impedance, temperature, heat transfer coefficient, entropy generation, and Bejan number, respectively. Also, the results are validated for velocity and temperature profiles for a given set of values of the dimensionless parameters. The entropy generation increases with rising values of shape parameter (n) up to a specific radius ( x 1 ∗ = 0.84 $x_1^*=0.84$ ) and then changes its behavior in the vicinity of the stenotic zone, in which entropy generation decreases with increasing values of shape parameter (n). The current findings may be helpful for biomedical scientists those are interested to investigate the treatment of various cardiovascular diseases (CVDs).

Hybrid nanoliquid flow through a microchannel with particle shape factor, slip and convective regime

Abstract: Purpose This study aims to portray the systematic study of hybrid nanofluid with particle shape effect on significant heat transfer enhancement. The steady flow of hybrid nanoliquid in a microchannel with the aid of porous medium has been considered. The dispersion of copper and Al2O3 in water is taken as hybrid mixture. The impact of thermal radiation, slip length and convective conditions on flow and thermal features are examined numerically. Design/methodology/approach The modelled equations are made dimensionless by means of nondimensional entities. The solutions are computed numerically by the implementation of Runge–Kutta-based shooting technique. The results depict that the shape of hybrid mixtures plays a significant role in convective heat transfer. Relevant results on flow velocity, temperature, Nusselt number and friction factor for various physical constraints have been perused. The obtained outcomes are displayed graphically. Findings The acquired results depict that Nusselt number augments with Eckert number and solid volume fraction of hybrid nanoparticles, which has a vibrant role in enriching the heat transfer coefficient. Also, it is emphasized that the Nusselt number is larger for blade-shaped nanoparticle compared to other shapes. Originality/value The analysis of individual effect of thermal radiation, Joule heating, viscous dissipation and magnetic field on the flow of Cu and Al2O3 hybrid nanofluid through microchannel has vivacious role in augmenting heat transmission. Along with this, the impact of porous medium, shape factor, slip and convective peripheral conditions are also emphasized.

Analysis of third‐grade liquid under the influence of wall slip and variable fluid properties in an inclined peristaltic channel

Abstract: The current model investigates the effect of wall slip on third‐grade liquid flow through an inclined peristaltic channel. The variation in viscosity and thermal conductivity are taken into account, along with wall properties. The governing equations are simplified using long wavelength and small Reynolds number approximations. The transformed equations are solved by using the perturbation technique. Physiological quantities such as velocity, streamlines, temperature, and concentration are obtained for different parameters of interest. The findings show that increasing the variable viscosity and slip term value improves the velocity profile. Furthermore, elasticity factors help flow, but damping causes fluid particles to slow down. Similarly, when the slip, variable viscosity, and inclination parameter values rise, the size of the trapped bolus grows, resulting in more bolus forms. Furthermore, the inclusion of variable properties helps understand the complex rheological properties of blood flowing through narrow or micro arteries.

Hydromagnetic flow of dusty fluid with heat and mass transfer past a stretching curved surface in a porous medium

Abstract: A steady two-phase fluid flow over a curved elongating sheet with dust particles has been scrutinized. Influence of volume fraction, applied magnetic field, buoyancy-driven force on the flow over a porous medium has been studied. Using similarity transformations, multivariable functions having partial derivatives in the problem for both fluid and dust phases are transmuted into ordinary differential equations. Then, emerging non-linear differential equations are formulated numerically by employing MATLAB built-in bvp4c solver scheme. Shapes of momentum, thermal and mass boundary layers have been shown by graphical forms for various values of flow parameters. Friction factor, heat and mass transfer rates are calculated and given in tabular forms.

Hydrodynamic Boundary Layer Flow of Chemically Reactive Fluid over Exponentially Stretching Vertical Surface with Transverse Magnetic Field in Unsteady Porous Medium

Abstract: This article addresses the hydrodynamic boundary layer flow of a chemically reactive fluid over an exponentially stretching vertical surface with transverse magnetic field in an unsteady porous medium. The flow problem is modelled as time depended dimensional partial differential equations which are transformed to dimensionless equations and solved by means of approximate analytic method. The results are illustrated graphically and numerically and compared with previously published results which shown a good agreement. Physically increasing Eckert number of a fluid amplifies the kinetic energy of the fluid, and as a novelty, the Eckert number under the influence of chemically reactive magnetic field is effective in controlling the kinematics of hydrodynamic boundary layer flow in porous medium. Interestingly, whilst the Eckert number amplifies the thermal boundary layer thickness and velocity as well as the concentration of the fluid, the presence of the magnetic field and the strength of the chemical reaction have a retarding effect on the flow. Also, the chemical reaction parameter and permeability of porous medium are effective in reducing skin friction in chemically reactive magnetic porous medium and are relevant in practice because reduced skin friction enhances the efficiency of a system. The results of the current study are useful in solar energy collector systems and materials processing.

Modeling and Optimal Control Analysis for Malaria Transmission with Role of Climate Variability

Abstract: In this paper, we present a nonlinear deterministic mathematical model for malaria transmission dynamics incorporating climatic variability as a factor. First, we showed the limited region and nonnegativity of the solution, which demonstrate that the model is biologically relevant and mathematically well-posed. Furthermore, the fundamental reproduction number was determined using the next-generation matrix approach, and the sensitivity of model parameters was investigated to determine the most affecting parameter. The Jacobian matrix and the Lyapunov function are used to illustrate the local and global stability of the equilibrium locations. If the fundamental reproduction number is smaller than one, a disease-free equilibrium point is both locally and globally asymptotically stable, but endemic equilibrium occurs otherwise. The model exhibits forward and backward bifurcation. Moreover, we applied the optimal control theory to describe the optimal control model that incorporates three controls, namely, using treated bed net, treatment of infected with antimalaria drugs, and indoor residual spraying strategy. The Pontryagin’s maximum principle is introduced to obtain the necessary condition for the optimal control problem. Finally, the numerical simulation of optimality system and cost-effectiveness analysis reveals that the combination of treated bed net and treatment is the most optimal and least-cost strategy to minimize the malaria.

Mathematical Analysis of Two Strains Covid-19 Disease Using SEIR Model

Abstract: The biggest public health problem facing the whole world today is the COVID-19 pandemic. From the time COVID-19 came into the limelight, people have been losing their loved ones and relatives as a direct result of this disease. Here, we present a six-compartment epidemiological model that is deterministic in nature for the emergence and spread of two strains of the COVID-19 disease in a given community, with quarantine and recovery due to treatment. Employing the stability theory of differential equations, the model was qualitatively analyzed. We derived the basic reproduction number for both strains and investigated the sensitivity index of the parameters. In addition to this, we probed the global stability of the disease-free equilibrium. The disease-free equilibrium was revealed to be globally stable, provided and the model exhibited forward bifurcation. A numerical simulation was performed, and pertinent results are displayed graphically and discussed.

Mathematical modelling and analysis of coffee berry disease dynamics on a coffee farm.

Abstract: This paper focuses on a mathematical model for coffee berry disease infestation dynamics. This model considers coffee berry and vector populations with the interaction of fungal pathogens. In order to gain an insight into the global dynamics of coffee berry disease transmission and eradication on any given coffee farm, the assumption of logistic growth with a carrying capacity reflects the fact that the amount of coffee plants depends on the limited size of the coffee farm. First, we show that all solutions of the chosen model are bounded and non-negative with positive initial data in a feasible region. Subsequently, endemic and disease-free equilibrium points are calculated. The basic reproduction number with respect to the coffee berry disease-free equilibrium point is derived using a next generation matrix approach. Furthermore, the local stability of the equilibria is established based on the Jacobian matrix and Routh Hurwitz criteria. The global stability of the equilibria is also proved by using the Lyapunov function. Moreover, bifurcation analysis is proved by the center manifold theory. The sensitivity indices for the basic reproduction number with respect to the main parameters are determined. Finally, the numerical simulations show the agreement with the analytical results of the model analysis.

Slip and temperature jump effects of MHD stagnation point flow towards a translating plate considering nonlinear radiations

Abstract: This article investigates the combined effects of nonlinear radiation and magnetic parameter under the velocity slip and temperature jump conditions on the boundary layer flow, arising in magnetohydrodynamics stagnation point flow toward a horizontal moving plate with constant velocity, U w ${U}_{w}$ . The governing mass, momentum, and energy equations are reduced into nonlinear ordinary differential equations with boundary conditions using the relevant similarity variables. The reduced boundary value problem is regulated by the magnetic parameter, slip parameter, temperature jump parameter, Prandtl number, radiation parameter, and temperature ratio parameter. In the absence of an analytic solution, the reduced equations are then demonstrated numerically using the shooting technique. The effects of parameters on the flow domain are analyzed using tables and figures. Moreover, two‐dimensional streamlines are plotted for visualizing fluid flow. It is found that the temperature decreases as the magnetic parameter, slip parameter, temperature jump parameter, and Prandtl number increase, but the opposite scenario is observed when the radiation parameter and temperature ratio parameter increase.

Mass Transfer Effects on the Mucus Fluid with Pulsatile Flow Influence of the Electromagnetic Field

Abstract: The influence of pulsatile flow on the oscillatory motion of an incompressible conducting boundary layer mucus fluid flowing through porous media in a channel with elastic walls is investigated. The oscillatory flow is treated as a cyclical time-dependent flux. The Laplace transform method using the Womersley number is used to solve non-linear equations controlling the motion through porous media under the influence of an electromagnetic field. The theoretical pulsatile flow of two liquid phase concurrent fluid streams, one kinematic and the other viscoelastic, is investigated in this study. To extend the model for various physiological fluids, we postulate that the viscoelastic fluid has several distinct periods. We also apply our analytical findings to mucus and airflow in the airways, identifying the wavelength that increases dynamic mucus permeability. The microorganism’s thickness, velocity, energy, molecular diffusion, skin friction, Nusselt number, Sherwood number, and Hartmann number are evaluated. Discussion is also supplied in various sections to investigate the mucosal flow process.

Co-dynamics of cassava virus disease with farming awareness and control measures: A case of lake zone in Tanzania

Abstract: : The cassava virus diseases co-dynamics model is formulated and analysed using ordinary differential equations theories. The modelling involves cassava plant and whitefly vector population, with aspects of Farmer's awareness level. The evaluation of farmers' awareness inverted numerically and found that increasing awareness levels among farmers decrease disease transmission and spread. The data from ten district councils in the Tanzania lake zone fit and estimate the model parameters. In addition, time-dependent controls were incorporated to reduce the burden on cassava farmers. The findings revealed that with limited resources, uprooting and burning the infected cassava plants and awareness campaign programs significantly reduce the transmission. Therefore, to overcome the burden caused by cassava virus diseases, the farmers are recommended to uproot and burn the infected cassava plants from the farm. Also, it should be updated on controlling disease through educational campaign programs to enhance farmers' awareness.

Magnetized Flow of Electrically Induced Maxwell Nanofluid over Reactive Stretching Plate with Thermal Stratification

Abstract: Effects of thermal stratification on magnetized flow of electrically induced Maxwell nanofluid over reactive stretching plate have been analyzed. The nonlinear ordinary differential equations governing the flow problem were obtained by applying Similarity transformation. The resulting model was then solved with the aid of the fourth order Runge-Kutta algorithm along with the shooting technique. Results for pertinent flow parameters were tabulated and analyzed graphically. The Richardson number was noted to appreciate the momentum boundary layer thickness but it decayed both the thermal and solutal boundary layer thicknesses.

A Review of the Mathematical Models for the Impact of Seasonal Weather Variation and Infections on Prey Predator Interactions in Serengeti Ecosystem

Abstract: Interaction between prey and predator species is a complex and non-linear process. Understanding various phenomena in the dynamics of prey-predator systems is vital to both mathematical ecology and conservation biology. Mathematical models on prey-predator systems have been the hot sport providing important information regarding the interactions of prey and predator species in various ecosystems. In this paper, a review of the available mathematical models on prey-predator systems was done. Our aim was to assess their structure, behaviour, available control strategies, population involved and their ability in predicting the future behaviour of the ecosystems. We observed diversities in the reviewed mathematical models, some model incorporated factors such as drought, harvesting and prey refuge as the factors that affect ecosystems, some ignored the contribution of environmental variations while others considered the variable carrying capacity. Most of the models reviewed have not considered the contribution of diseases and seasonal weather variation in the dynamics of prey predator systems. Some of the reviewed models do not match the real situation in most modelled ecosystems. Thus, to avoid unreliable results, this review reveals the need to incorporate seasonal weather variations and diseases in the dynamics of prey predator systems of Serengeti ecosystem.

Effects of Temperature Fluctuations on Darcy-Forchheimer Flow of Oil-Based Nanofluid with Activation Energy and Velocity Slip

Abstract: The effects of fluctuating temperature on Darcy-Forchheimer flow of oil-based nanofluid with activation energy and velocity slip has been analyzed. Similarity transformation was used to transform the governing partial differential equations into coupled nonlinear ordinary differential equations and solved numerically with the aid of the fourth order Runge-Kutta algorithm with a shooting technique. Results for the embedded parameters controlling the flow dynamics have been tabulated and illustrated graphically. The slip velocity parameter was found to enhance the Nusselt number but depleted both the skin friction coefficient and Sherwood number while the local inertial was noted to increase both the skin friction coefficient and Sherwood number but diminishes the Nusselt number. These results indicate that the velocity slip parameter and local inertial coefficient can be used to control flow characteristics in industrial and engineering systems.

Natural convection and heat transfer of micropolar hybrid nanofluid over horizontal, inclined and vertical thin needle with power-law varying boundary heating conditions

Abstract: The current investigation may be utilized significantly in the modern industrial technologies to provide better cooling environment in the outer surface as well as micro scale level such as blood transportation, lubrication, wind velocity measurement, wire coating, and aerodynamics etc. The present problem explores the various aspects of natural convection flow and heat transfer of micropolar hybrid nanofluid. The fluid flow is taken for horizontal, inclined and vertical positions of moving thin needle under quadratic thermal radiation effects. The governing equations are non-dimensionalized by using relevant similarity transformations. BVP4C in MATLAB use these equations to obtain the required solutions. These solutions help in analysing the important aspects of the flow i.e., velocity, microrotation, temperature, skin friction and Nusselt number profiles for different parameters utilizing graphical representation. From these results we observe that velocity of the fluid velocity has been declined with rise in magnetic parameter. The reverse trend is the result for temperature profile in response to Sundry radiation parameter. Further, heat transfer rate is intensified at all positions of moving thin needle subject to power law variation of surface heat flux than power law variation of wall temperature.

Second law analysis of MHD convection of a radiating nanofluid within the gap between two inclined concentric pipes

Abstract: This paper theoretically examined the inherent irreversibility in hydromagnetic mixed convection of a radiating adjustable viscosity nanofluid between two concentric inclined cylindrical pipes. Thermodynamics’ first and second laws are incorporated into the two-phase nanofluid flow model problem to explore the repercussions of thermophoresis, Brownian motion, inclination angle, Joule heating, buoyancy forces, viscous dissipation, thermal radiation and entropy generation rate on the overall flow structure with temperature and nanoparticles concentration distribution. The nonlinear model equations of differential types are obtained and numerically addressed through shooting quadrature in conjunction with the Runge–Kutta–Fehlberg integration scheme. Relevant outcomes are graphically represented and discussed. The findings indicate that a rise in the inclination angle lessens the buoyancy effects and diminishes the entropy generation rate in the annular region of the concentric pipes. Within the annulus, the irreversibility due to heat and mass transfer dominates the entropy generation rate. In contrast, an upsurge in magnetic field intensity decreases the entropy generation rate and the Bejan number.

Establishment of Impulsive and Accelerated Motions of Casson Fluid in an Inclined Plate in the Proximity of MHD and Heat Generation

Abstract: This article is committed to examine the unsteady MHD Casson liquid flow in an inclined infinite vertical plate in the proximity of heat generation and thermal radiation. The governing energy and momentum partial differential equations are ascertained. The momentum equation is established for two distinct types of conditions when the magnetic domain is relevant to the liquid and the magnetic domain is relevant to the moving plate. Analytical expressions for liquid temperature and motion are acquired by applying Laplace transform technique. The effects of physical parameters are accounted for two distinct types of motions namely impulsive motion and accelerated motion. The numerical values of liquid motion and temperature are displayed graphically for various values of pertinent flow parameters. A particular case of our development shows an excellent compromise with the previous consequences in the literature.

Transient Dynamics Of Pressure-Driven Encroachment in narrow Conduits with Rate-Dependent body Force

Abstract: We analytically explore the flow of a Newtonian liquid forced to encroach a narrow tube of uniform cross-section, by an unsteady pressure gradient, assisted by an encroachment-rate dependent external force. This novel problem is thought to have interesting implications. For instance in medicine where narrow tubes like syringes and needles are typically used to administer medication and in the printing industry. Using an unsteady eigenfunction expansion, the velocity distribution is accurately defined to yield unsteady profiles, contrasting with the classical Poiseuille parabola. We subsequently used our unsteady spectral decomposition to properly capture the kinematics and dynamics hidden in the models. The comparison of the rectangular and circular channels shows as model ducts yield interesting similarities that can inform the choices of channels.By a detailed comparison between rectangular and circular channels, we show that such model ducts yield interesting similarities that can inform the choices of channels. Moreover, we obtain short and long-time dynamic behaviors, captured using a robust perturbation scheme that elegantly highlights the early and long-time characteristics. In the end, we present plots for encroachment depth and rate and the early and long-term asymptotic approximations and appropriately their graphical trends.

Mathematical Model of Potato virus y disease spread with Optimal control

Abstract: Potato virus Y (PVY) is an aphid-borne plant virus that causes substantial yield losses in potato production. Control measures of the viral infection are both limited and expensive. A proper use of mixed-cropping strategy can reduce the spread of PVY. In this paper, we formulate and analyze a mathematical model of PVY spread in a mixed-cropping system. Then, we extend the model to an optimal control problem by considering use of mineral oil, insecticide and farmer’s level of field inspection for infected plants. The analytic results show that the basic reproduction number ℜ0, a threshold parameter that decides properties of the dynamics. The disease free equilibrium is stable if ℜ0 < 1 and unstable when ℜ0 > 1. It is found that ℜ0, and hence, the disease dynamics is highly sensitive to the representative parameters of density the non-host plant and its quality in attracting vectors. The model exhibits forward bifurcation at ℜ0 = 1. The study of optimal control problem suggests that mixed-cropping combined with either mineral oil or insecticide is the best to control the disease. Furthermore, simulation results show that mixed-cropping can be used as an alternative strategy and can reduce the need of mineral oil or insecticide.